Power press



J. c. L EDBETTER POWER PRESS Aug. 30 1927. 1,640,609

Filed April 2, 1924 INVENTOR "James C. Zedezfer BY I I b 6 RNEYS ing Patented Aug. 30, 1927.

UNITED STATES PATENT OFFICE.

J'AMES C. LEDBE'ITER, OF- BROOKLYN, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENU-S, TO THE PROSPERITY COMPANY, INC A CORPORATION OF NEW YORK.

POWER PRESS.

Application filed April 2, 1924. Serial 1th. 703,593.

This invention relates to pressing machinery and particularly to power press improvements.

The main object of the invention is to produce a high powered pressing machine possessing a mode of operationeinherentlysafe whereby an operator is compelled to use one hand to close the press and the other hand to start the motormeans to impose high compression between the press jaws, and in this way the operator is restrained against leaving one hand in the press to spread the work thereupon during the closmotion of the jaws.

An additional obi'ject of the invention is to interpose a dou balancing factor for opening the pressing machine when the operator removes his hand from the closing means or for opemng the press when the motor means remains or reaches normal inactive non-pressing position. In other words I rovlde one overbalancing means just slig tly heavier than the press head for lifting said head high above the buck together with another overbalancing means so operating as to permit the said first overbalancing means to go into operation.

- I have so improved the pressing machine in respect to its structure and mode of operation that unnecessary booster levers or pressure producing toggles are not employed. While I employ a toggle linkage for transmitting the thrust produced by the motor means, I do not employ a toggle for developing the thrust itself. Likewise in my improvements, I do not employ a power multiplying booster lever acted upon by motor means, but utilize only the direct thrust as produced by a. motor driven cam. The machine is improved in respect to its hand closing means operated manually in conjunction with a motor controlling device likewise operated manually.

The accompanying drawing illustrates a preferred form of the invention but certain changes in construction and operation may be made without departing from the scope and principle of the invention.

Figure 1 illustrates a side view of the power press in closed position undergoing high compression.

Figure 2 illustrates a fragmentary view of the lost motion connected swing link and le or compound over pressure link showing said parts in their position when the press head is down but prior to the imposition of high compression thereon.

Referring now more particularly to the drawings for a detailed description of the invention, there is shown a pressing machine frame 10 some parts of which are broken away for clearness in illustration and a press buck '11 is supported on the frame together with a press lever 12 pivoted at 13 on the frame. The forward end of the press lever carries a pressing head or jaw 14 which rises and lowers in conjunction with the buck 11. A handle 15 is carried on the forward end of the press lever or upon the head and usually comprises a wooden bar by which the operator closes the head 14 down upon the buck 11. The pressing machine is so constituted that the operator easily pulls the head 14 down by one hand and this operation is executed without great effort because a counterbalancing weight 16, while slightly heavier than the head 14, is preferably just heavy enough to lift the head 14 should'the operator remove his hand from the handle 15. A link 18 is pivoted at 19 on the-rear end of the press lever and has a pin 20 fixed in the lower end thereof. This pin 20 is adapted to freely slide in a slot 21 of a thrust link 22. The thrust link is made with an eccentric strap 23 on the lower end thereof which. is pivotally or rotatably confined on a cam 24 connected with and driven by a shaft 25.

An overbalancing arm 27 has its lower end pivoted on the frame 10' at 28 with its upper end pivotally connected to the link 18 by a pivot pin 29. This link 27 is preferably weighted as upon' the upper end thereof or.usually this arm is sufiiciently heavy for the purposes intended without any special weighting means as long as the said link has enough body or stock to impose a slight outward pressure or overbalancing tendency on and against the link 18 to cause the said connected links 18 and 22 to be continuously urged outwardly towards a rear broken position as indicated by the dotted line position of arts. When the o erator draws the hea 14 down upon t e work spread upon the buck 11, he does so against the very slight opposition offered by the weight 16 and weighted member 27, but once the head 14 is down upon the buck, the linkage 18-22 has reached an overstraightened position to the extent that the axls of the center pin has "passed beyond the plane passing through the axis of the pin 19 and shaft which is to say/ that the said lost motion center pin 20 has passed beyond the center line LL. This arrangement of parts so sets up and constitutes the linkage 1822 that they are held rigid when the cam 24 rotates upwardly to impart thrust through the linkage. The weighted arm 27 holds the straightened link parts 18 and 22 win the overstraightened position and pre-- vents said links from moving inwardly any further. In other words the arm 2? acts as a brace to prevent the connected links 18 and 22 from moving inwardly but will permit, and in fact actually causes the said links to quickly swing outwardly as shown in dotted line position of parts.

The shaft 25 already described is fixed to a worm wheel 32 contained within a gear housing 33. The worm wheel is driven by a worm pinion 34 which is in turn driven by a power shaft 35 usually equipped with a fly wheel 36 to impart momentum and all of which is in turn. driven by 'an electric motor 37. Usually the motor is arranged to run continuously and in such case clutchin means may be provided for stopping an starting the cam" 24. It is understood, however. that the motor 37 may be alternately stopped and started to drive the cam to lower-most position and upper-most position durin ordinary operation of the press. I provide a control handle 39 for.operat ing either a clutching mechanism for stopping and starting the cam or for operating a switching mechanism for stopping and starting the motor but in the present illustration, the control handle 39 is fixed to a shaft 40 which acts to swing a pendulous member 41 in and out against the clutch lever 42 extending down into the gear housing 33. In cases where a continuously running electric motor 37 is employed for operating the pressing machine, any approved form of clutch lever 42 may extend into the gear housing 33 for engaging and disengaging any suit-able form of clutching mechanism to start and stop the cam 24. Neither the clutching mechanism nor the switching .mechanism constitutes any part of this invention and are omitted. for clearness 1n d1s-- closure, but it will be understood by those conversant with the art just how the said control handle 39 is utilized for controlling shown in Figure 2 which loosens up the 10st motion connection 2021 causing a portionof the slot 21 to appear below the pin 20. This produces a looseness which instantly permits the weighted arm 27 to swing outwardly and downwardly carrying the link 18 with it into dotted line position shown in ried out without any effort on the part ofthe operator and constitutes an advanced improvement in the art for many pressing machines in present day use employ a kick off pedal for opening the press but in my improvements, the opening thereof is incident to the rotation of the cam 24 from high position in Figure 1' to low position Figure 2.

After the work is spread upon the buck 11, the operator uses one hand to draw the head 14 down by pulling on the handle 15. Should the operator release his hand from the head handle 15 the press immediately opens due to the fact that the overbalancing factor inherent in the weighted arm 27 and counterweight 16 instantly act to swing downwardly on the press lever 12. It is noted therefore that the operator cannot expect to close the head with one hand and then move that hand to the cam starting handle 39 for the weighted member27 acts too quickly and pushes the center pin 20 beyond the plane L before the motor means can be a plied. The operator must therefore hold t 6 head down with one hand and start the motor means with the other hand and this mode of operation positively insures against ,slot 21 by bringing the bottom end thereof up against the pin 20 whereupon the link 18 is given a distinct short upward thrust of great force to impose compression between the pressing jaws.

What I claim is:

1. A machine comprising in combination, cooperating pressing members, a pivotal press lever carrying a pressing head on one end thereof adapted to be manually closed, a swing link pivotally suspended on the other end thereof, a thrust link having a lost motion connection with the lower end of the swing link, motor means supporting the thrust 2. A machine comprising in combinationcooperating pressing members, a pivotal press lever carrying a pressing head on one end thereof adapted to be manually closed, a swing link pivotally suspended onvthe other end thereof, a thrust link having a lost motion connection with the lower end of the swing link, motor means supporting the thrust link and adapted to push upwardly thereon, and a device connected with the swing link and thrust link for breaking them away from straight line position should the operator remove his hand from the head before the motor means acts.

3. A machine comprising in combination,-

end thereof adapted to be manually closed,

a swing link pivotally suspended on the other end thereof, a thrust link having a lost motion connection with the lower end of the swing link, motor means supporting the thrust link and adapted to push upwardly thereon, an overbalancing means operating on the press lever to open the press when the operator removes his hand from said lever, a manually operable control handle by which the operator sets the motor means in operation with one hand .while he holds the press closed with the .otherhand, and means which breaks the swing link andthrust link away from straight line only when the motor means is not functioning and when the overbalancing means is functioning.

4. A'machine comprising in combination, cooperating pressing members, a pivotal press lever carrying a pressing head on one end thereof adapted to be manually closed, a swing link pivotally suspended on the other end thereof,athrust link having alost motion connection with the lower end of the swing link, motor means supporting the thrust link and adapted topus'h upwardly thereon and take up the lost motion existing in the swing link and thrust link, an overbalancing. weight continuously lifting upwardly on the pressing head, a weighted arm having pivotal connection with the swing link and thrust link and leaning outwardly thereagainst tending to break the linkage rear-- wardly and open the press. I

5. 'A machine comprising in combination, cooperating pressing members, a pivotal press lever carrying a pressing head on one end thereof adapted to be manually closed, a swing link pivotally suspended on the other end thereof, a thrust link havin a lost motion connection with the lower on of the swing link, motor means supporting the thrust link and adapted to push upwardly thereon and take up the lost motion existing in the'swing link and thrust link, an overbalancing weight continuously liftin upwardly on the pressing head, a weighte arm having pivotal connection with theswing link and thrust link and leaning .outwardly thereagainst tending to break the linkage rearwardly and open the press, and a manually controlled device operable by the other hand of the operator to start the motor means.

6. A ower press comprising in combination, a rame, a press lever pivoted thereon, pressin members made to open' and close one against the other by the operation of the press lever, means imposing an overbalancing factor on the press lever to continuously open the press, a handle carried by one pressing member by which the operator closes the press against the opening tendency of the overbalancing factor, a swing link having the upper end thereof pivotally connected to the press lever, a thrust lever pivotally connected to the lower end of the swing link, a slotted lost motion connection existing at the point of connection between the swing link and thrust link, an eccentric strap made on the lower end of the thrust link, a cam rotatably confined in the eccentric, motor means to drive the cam and produce a force through the thrust link, a manually operable device for controlling the motor means and the rotation of theham, an overbalancing arm having its lower end pivoted .on the frame and its upper end pivotally connected with the swin link, said overbalancing arm being weighte to impose an outward thrust on the lost motion link connected parts, and the mode of operation being such that the oper- .ator must hold the headdown with one hand and start the motor means with the other hand.

In testimony whereof I aflEix my signature JAMES C. LEDBETTER. 

